Heat exchanger package with split radiator and split charge air cooler

ABSTRACT

A combined radiator and charge air cooler package includes a radiator having upper and lower portions for cooling engine coolant and a charge air cooler having upper and lower portions for cooling charge air. The upper charge air cooler portion is disposed in overlapping relationship and adjacent to the upper radiator portion, and the lower charge air cooler portion is disposed in overlapping relationship and adjacent to the lower radiator portion. The upper radiator portion and the lower charge air cooler portion are aligned in a first plane, and the lower radiator portion and the upper charge air cooler portion are aligned in a second plane, behind the first plane. Ambient cooling air may flow in series through the upper radiator portion and the upper charge air cooler portion, and also through the lower charge air cooler portion and the lower radiator portion.

This is a continuation-in-part of U.S. application Ser. No. 10/723,881filed Nov. 26, 2003.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to heat exchanger devices for cooling fluids usedin an internal combustion engine, and more particularly, to a heatexchanger package including a coupled radiator and charge air cooler foran engine of a motor vehicle such as a heavy-duty highway truck or bus.

2. Description of Related Art

Heat exchanger packages comprising a radiator and a charge air cooler(CAC), also known as an intercooler, have been used for years in overthe road highway trucks and buses and other heavy-duty motor vehicles.The radiator provides cooling for the engine coolant, usually a 50-50solution of water and anti-freeze. The charge air cooler receivescompressed, charge or intake air from the turbo- or super-charger andlowers its temperature before it enters the engine intake manifold,thereby making it denser, improving combustion, raising power output,improving fuel economy and reducing emissions. In order to optimize heattransfer in a given heat exchanger package size, the factors of coolingair flow, heat exchanger core restriction, cooling air flow split andcooling air approach and differential temperature must be balanced.

Numerous configurations of the radiator/charge air cooler heat exchangerpackage have been disclosed in the prior art. Placing both the radiatorand charge air cooler side-by-side or vertically (as in U.S. Pat. No.4,736,727), so that the full frontal area of each of the cores areexposed to ambient cooling air, provides the best performance, butrequires the largest package frontal area. Limitations in the frontalarea of radiator and charge-air cooler heat exchanger packages have beensought in order to accommodate the smaller frontal area of motorvehicles, as a result of improved vehicle aerodynamics. Heat exchangerpackages with smaller frontal areas have been disclosed for example inU.S. Pat. Nos. 5,046,550, 5,316,079, 6,619,379 and 6,634,418, and inU.S. patent application Ser. No.10/289,513.

In another prior art radiator and charge air cooler heat exchangerpackage, depicted in FIG. 1, the charge air cooler is split between anupper unit 101 and a lower unit 103, disposed respectively behind and infront of radiator 107 with respect to the direction of cooling air flow127. Radiator 107 has a conventional downflow-type tube and fin core 117between upper tank 109 a and lower tank 109 b. Radiator 107 receivescoolant 131 from the engine into upper tank 109 a and the cooled enginecoolant exits as 133 from the lower portion of lower tank 109 b, to betransferred back to the engine. Both charge air cooler units 101, 103are cross-flow type charge air coolers wherein the compressed charge airis flowed horizontally through the respective tube and fin cores 111,113. Compressed, heated charge air 121 is first flowed into verticallyoriented tank 105 a of upper charge air cooler 101, through core 111 indirection 129 a, and into vertical tank 105 b. In unit 101, the chargeair is cooled by air 127 as it exits the upper portion of radiator core117. Thereafter, the partially cooled compressed charge air 123 is thentransferred into vertical tank 105 d of lower charge air cooler 103,where it is then flowed in horizontal direction 129 b through core 113and into vertical tank 105 c, and thereafter exits 125 and flows to theengine intake manifold. In unit 103, the charge air is cooled by air 127before it flows through the lower portion of radiator core 117.Notwithstanding its novel design, the heat exchanger package of FIG. 1did not achieve good performance and did not go into normal production,to the inventor's knowledge. It has now been determined that theperformance of the heat exchanger package of FIG. 1 suffered in largepart due to excessive charge air pressure drop through the two chargeair cooler units.

There is urgent need for greater engine cooling capacity in the highwaytrucks of the near future. One factor is the enactment of more stringentemission regulations which will become effective in 2007. Many enginemanufacturers plan to meet the new requirements by means of exhaust gasrecirculation (EGR), in which a portion of the engine exhaust gas isrecirculated to the intake manifold for reburning. In this method,exhaust gas coolers are used to lower the temperature of the exhaust gasbefore it enters the intake manifold. The heat load from these coolersis added to the normal engine cooling heat load, requiring increasedcooling capacity from the engine cooling system. The second factor isthe demand by truck owners and operators for increased horsepower outputin new trucks. Higher power output can contribute to higher averagespeeds over hilly terrain, shortening trip times and increasing profits.However, higher power output requires increased cooling capacity.

This need for increased cooling capacity poses a dilemma for truckbuilders that have recently invested heavily in aerodynamic styling fortheir trucks. The sloping hoods of new trucks seen on the highway todayare a result of this restyling, which places extreme limitations on thesize of the engine cooling package. At the present time, truckmanufacturers are seeking a solution to the problem of providingincreased cooling capacity without costly redesign of the truck frontend, which includes the hood, grille, bumper and fenders. Thus there hasbeen a long-felt need to achieve high performance in cooling both enginecoolant and charge air, while observing strict limitations in charge airpressure drop and frontal area of a radiator/charge air cooler heatexchanger package.

SUMMARY OF THE INVENTION

Bearing in mind the problems and deficiencies of the prior art, it istherefore an object of the present invention to provide a combinationradiator and charge air cooler which achieves high heat transferperformance with a minimal frontal area.

It is another object of the present invention to provide a heatexchanger package for cooling different fluids which minimizes thepressure loss to the fluids.

It is a further object of the present invention to provide a method ofcooling fluids such as engine coolant and charge air used in the engineof a motor vehicle which optimizes heat transfer of those fluids toambient cooling air.

The above and other objects, which will be apparent to those skilled inthe art, are achieved in the present invention which is directed to aheat exchanger apparatus comprising: a first heat exchanger having twoportions for cooling a first fluid. Each first heat exchanger portionhas opposite front and rear faces through which cooling air flows,opposite first and second ends adjacent the faces, sides adjacent thefaces between the first and second ends, and includes tubes throughwhich the first fluid may flow while being cooled. The heat exchangerapparatus also includes a second heat exchanger having two portions forcooling a second fluid, with each second heat exchanger portion havingopposite front and rear faces through which cooling air flows, oppositefirst and second ends adjacent the faces, and sides adjacent the facesbetween the first and second ends, and including tubes through which thesecond fluid may flow while being cooled.

One of the second heat exchanger portions is disposed in overlappingrelationship and adjacent to one of the first heat exchanger portions,such that one face of the one of the first heat exchanger portions isdisposed adjacent one face of the one of the second heat exchangerportions, such that the ambient cooling air may flow in series throughthe one of the first heat exchanger portions and the one of the secondheat exchanger portions. The other of the second heat exchanger portionsis disposed in overlapping relationship and adjacent to the other of thefirst heat exchanger portions, such that the other face of the other ofthe first heat exchanger portions is disposed adjacent one face of theother of the second heat exchanger portions. In this manner, the coolingair may flow in series through the other of the second heat exchangerportions and the other of the first heat exchanger portions.

The first and second heat exchanger portions have heights between thefirst and second ends thereof, and the heights of the ones of the firstand second heat exchanger portions may be greater than the heights ofthe others of the first and second heat exchanger portions, or may besubstantially the same. The heights of the first and second heatexchanger portions also may all be different.

The first and second heat exchanger portions have widths between thesides thereof, and the widths of the first heat exchanger portion may begreater than the widths of the second heat exchanger portion, or may besubstantially the same.

In a related aspect, the present invention provides a method for coolingfluids used in an internal combustion engine comprising providing a heatexchanger assembly as described above. The method then includes flowingthe first fluid in series or parallel through the first heat exchangerportions and flowing the second fluid in series between the one and theother of the second heat exchanger portions. The method also includesflowing ambient cooling air through the heat exchanger assembly suchthat ambient cooling air flows in series through the one of the firstheat exchanger portions and the one of the second heat exchangerportions, and ambient cooling air flows in series through the other ofthe second heat exchanger portions and the other of the first heatexchanger portions. As used herein, the term ambient air includes all ofthe cooling air as it passes through the heat exchanger package, eventhough it is heated as it passes through the fins of the radiator andCAC units.

In practicing the method, the first fluid may flow in parallel throughthe first heat exchanger portions, with one portion of the first fluidflowing through the one of the first heat exchanger portions and anotherportion of the first fluid flowing through the other of the first heatexchanger portions. Alternatively, the first fluid may flow in seriesthrough both of the first heat exchanger portions, with all of the firstfluid flowing through both first heat exchanger portions.

Preferably, the first heat exchanger portions include a manifold alongeach of the sides with the first heat exchanger portion tubes connectingthe manifolds, and the first fluid flows from one side of the first heatexchanger portions to the other side of the first heat exchangerportions through the tubes. The first heat exchanger portions may beoperatively connected such that the first fluid flows between the one ofthe first heat exchanger portions and the other of the first heatexchanger portions adjacent at least one side of the first heatexchanger portions.

The second heat exchanger portions are operatively connected such thatthe second fluid may flow in series between the one and the other of thesecond heat exchanger portions. The second heat exchanger portions mayinclude a manifold between each of the sides at upper and lower ends ofeach of the portions with the second heat exchanger portion tubesconnecting the manifolds, such that the second fluid flows between oneend of the second heat exchanger portions and the other end of thesecond heat exchanger portions through the tubes. A down flow system maybe employed wherein the second fluid flows from the lower manifold ofthe one of the second heat exchanger portions to the upper manifold ofthe other of the second heat exchanger portions. Alternatively, anupflow system is employed wherein the second fluid flows from the uppermanifold of the other of the second heat exchanger portions to the lowermanifold of the one of the second heat exchanger portions. The secondheat exchanger portions may be operatively connected such that thesecond fluid flows therebetween through a conduit extendingsubstantially across the widths of the second heat exchanger portions.

The second heat exchanger portions may be up- or down flow units, andinclude a manifold between each of the sides at upper and lower ends ofeach of the portions with the second heat exchanger portion tubesconnecting the manifolds. Where the second heat exchanger portions aredown flow units, the one of the second heat exchanger portions hasgreater thickness between faces than the other of the second heatexchanger portions. Alternatively, where the second heat exchangerportions are upflow units, the other of the second heat exchangerportions has greater thickness between faces than the one of the secondheat exchanger portions.

Preferably, the one of the first heat exchanger portions and the otherof the second heat exchanger portions are disposed in a substantiallysame first plane, and the other of the first heat exchanger portions andthe one of the second heat exchanger portions are disposed in asubstantially same second plane. The ambient cooling air then flowssimultaneously through the one of the first heat exchanger portions andthe other of the second heat exchanger portions, and simultaneouslythrough the one of the second heat exchanger portions and the other ofthe first heat exchanger portions.

Preferably, the first heat exchanger is a radiator and the first fluidis engine coolant, and wherein the second heat exchanger is a charge aircooler and the second fluid is charge air, with each of the radiator andthe charge air cooler portions being cooled by ambient air.

In a preferred embodiment, the present invention is directed to acombined radiator and charge air cooler package comprising a radiatorhaving upper and lower portions for cooling engine coolant, and a chargeair cooler having upper and lower portions for cooling charge air. Eachradiator portion has opposite front and rear faces through which ambientcooling air flows, opposite upper and lower ends adjacent the faces, andsides adjacent the faces between the upper and lower ends, and includemanifolds between the sides at upper and lower ends of each of theradiator portions and tubes through which the engine coolant may flowconnecting the radiator manifolds. Each charge air cooler portion hasopposite front and rear faces through which cooling air flows, oppositeupper and lower ends adjacent the faces, and sides adjacent the facesbetween the upper and lower ends, and includes manifolds along the upperand lower ends and tubes through which the charge air may flowconnecting the charge air cooler manifolds.

The upper charge air cooler portion is disposed in overlappingrelationship and adjacent to the upper radiator portion, with one faceof the upper radiator portion being disposed adjacent one face of theupper charge air cooler portion, such that the ambient cooling air mayflow in series through the upper radiator portion and the upper chargeair cooler portion. The lower charge air cooler portion is disposed inoverlapping relationship and adjacent to the lower radiator portion,with the other face of the lower radiator portion being disposedadjacent one face of the lower charge air cooler portion, such that theambient cooling air may flow in series through the lower charge aircooler portion and the lower radiator portion. The upper radiatorportion and the lower charge air cooler portion are substantiallydisposed in one plane, and the lower radiator portion and the uppercharge air cooler portion are substantially disposed in another plane.The radiator portions are operatively connected such that the enginecoolant may flow in series or parallel through the radiator portions.The charge air cooler portions are operatively connected such that thecharge air may flow in series between the upper charge air coolerportion and the lower charge air cooler portion.

The radiator portions may be operatively connected such that the enginecoolant flows in parallel through the radiator portions, with oneportion of the coolant flowing through the upper radiator portion andanother portion of the coolant flowing through the lower radiatorportion. Alternatively, the radiator portions are operatively connectedsuch that the engine coolant may flow in series through both of theradiator portions, with all of the coolant flowing through both radiatorportions.

The upper charge air cooler portion may have a greater or lesserthickness between faces than the lower charge air cooler portion.

In another aspect, the present invention is directed to a heat exchangerapparatus comprising a first heat exchanger having two portions forcooling a first fluid. Each first heat exchanger portion has oppositefront and rear faces through which ambient cooling air flows, oppositefirst and second ends adjacent the faces, and sides adjacent the facesbetween the first and second ends. The heat exchanger package furtherincludes a second heat exchanger having two portions for cooling asecond fluid. Each second heat exchanger portion has opposite front andrear faces through which air flows, opposite first and second endsadjacent the faces, and sides adjacent the faces between the first andsecond ends, and includes manifolds at the first and second ends andfluid-carrying tubes extending substantially directly therebetween.

One of the second heat exchanger portions is disposed in overlappingrelationship and adjacent to one of the first heat exchanger portions,with the first and second ends of the one of the second heat exchangerportions being oriented in the same direction as the first and secondends of the one of the first heat exchanger portions. One face of theone of the first heat exchanger portions is disposed adjacent one faceof the one of the second heat exchanger portions, such that the ambientcooling air may flow in series through the one of the first heatexchanger portions and the one of the second heat exchanger portions.The other of the second heat exchanger portions is disposed inoverlapping relationship and adjacent to the other of the first heatexchanger portions, with the first and second ends of the other of thesecond heat exchanger portions being oriented in the same direction asthe first and second ends of the other of the first heat exchangerportions. The other face of the other of the first heat exchangerportions is disposed adjacent one face of the other of the second heatexchanger portions, such that the ambient cooling air may flow in seriesthrough the other of the second heat exchanger portions and the other ofthe first heat exchanger portions.

The first heat exchanger portions are operatively connected such thatthe first fluid may flow between the second manifold of the one of thefirst heat exchanger portions and the first manifold of the other of thefirst heat exchanger portions. The second heat exchanger portions areoperatively connected such that the second fluid may flow between thesecond manifold of the one of the second heat exchanger portions and thefirst manifold of the other of the second heat exchanger portions.

Preferably, the one of the first heat exchanger portions and the otherof the second heat exchanger portions are disposed in substantially thesame plane, and the other of the first heat exchanger portions and theone of the second heat exchanger portions are disposed in substantiallythe same plane.

The first heat exchanger portions may be operatively connected such thatthe first fluid may flow between the second manifold of the one of thefirst heat exchanger portions and the first manifold of the other of thefirst heat exchanger portions adjacent at least one side of the firstheat exchanger portions, or around at least one side of the second heatexchanger portions. The second heat exchanger portions may beoperatively connected such that the second fluid may flow therebetweenthrough a conduit extending from and along the second manifold of theone of the second heat exchanger portions to and along the firstmanifold of the other of the second heat exchanger portions.

The first heat exchanger portions typically include fluid-carryingtubes, with the fluid-carrying tubes of each of the first heat exchangerportions extending in the same direction as the fluid-carrying tubes ofeach of the second heat exchanger portions.

Preferably, the dimension between the first and second ends of thesecond heat exchanger portions is less than the dimension from one sideof the second heat exchanger portions to the other side of the secondheat exchanger portions, such that the fluid-carrying tubes extendacross the shorter dimension of the faces of the second heat exchangerportions. Additionally, the sides of the first heat exchanger portionsare aligned with the sides of the second heat exchanger portions, thefirst end of the one of the first heat exchanger portions is adjacentthe first end of the one of the second heat exchanger portions, and thesecond end of the other of the first heat exchanger portions is adjacentthe second end of the other of the second heat exchanger portions.

The second end of the one of the first heat exchanger portions may beadjacent the first end of the other of the first heat exchangerportions, and the second end of the one of the second heat exchangerportions may be adjacent the first end of the other of the second heatexchanger portions.

The manifolds of the first and second heat exchanger portions may extendhorizontally, such that the first and second heat exchanger portions arevertically separated, or the manifolds of the first and second heatexchanger portions may extend vertically, such that the first and secondheat exchanger portions are horizontally separated.

In alternate embodiments, at least one of the sides or ends of one ofthe first heat exchanger portions extends outward of a side or end ofone of the second heat exchanger portions. The first end of the one ofthe first heat exchanger portions may extend outward of the first end ofthe one of the second heat exchanger portions, and the second end of theother of the first heat exchanger portions extends outward of the secondend of the other of the second heat exchanger portions. Also, at leastone of the sides or ends of one of the second heat exchanger portionsextends outward of a side or end of the one of the first heat exchangerportions.

In another aspect, the present invention is directed to a method forcooling fluids used in an engine of a motor vehicle comprising providinga heat exchanger assembly as described above. The method then includesflowing the first fluid through the first heat exchanger portions, andflowing the second fluid through the substantially directly extendingtubes of the second heat exchanger portions and between the secondmanifold of the one of the second heat exchanger portions and the firstmanifold of the other of the second heat exchanger portions. The methodalso includes flowing cooling air through the heat exchanger assemblysuch that ambient cooling air flows in series through the one of thefirst heat exchanger portions and the one of the second heat exchangerportions, and ambient cooling air flows in series through the other ofthe second heat exchanger portions and the other of the first heatexchanger portions.

In practicing the method, preferably the second fluid flows in sequencethrough the first manifold of the one of the second heat exchangerportions, the substantially directly extending tubes of the one of thesecond heat exchanger portions, the second manifold of the one of thesecond heat exchanger portions, the first manifold of the other of thesecond heat exchanger portions, the substantially directly extendingtubes of the other of the second heat exchanger portions, and the secondmanifold of the other of the second heat exchanger portions.

The second fluid may alternatively flow in sequence through the secondmanifold of the other of the second heat exchanger portions, thesubstantially directly extending tubes of the other of the second heatexchanger portions, the first manifold of the other of the second heatexchanger portions, the second manifold of the one of the second heatexchanger portions, the substantially directly extending tubes of theone of the second heat exchanger portions, and the first manifold of theone of the second heat exchanger portions.

Preferably, the first heat exchanger is a radiator and the first fluidis engine coolant, and wherein the second heat exchanger is a charge aircooler and the second fluid is charge air, each of the radiator and thecharge air cooler portions being cooled by ambient air.

In its more preferred embodiment, the present invention is directed to acombined radiator and charge air cooler package including a radiatorhaving upper and lower portions for cooling engine coolant. Eachradiator portion has opposite front and rear faces through which ambientcooling air flows, opposite upper and lower ends adjacent the faces, andsides adjacent the faces between the upper and lower ends. The morepreferred package also includes a charge air cooler having upper andlower portions for cooling charge air. Each charge air cooler portionhas opposite front and rear faces through which cooling air flows,opposite upper and lower ends adjacent the faces, and sides adjacent thefaces between the upper and lower ends, and includes manifolds at theupper and lower ends and charge air-carrying tubes extendingsubstantially directly therebetween.

The upper charge air cooler portion is disposed in overlappingrelationship and adjacent to the upper radiator portion, with the upperand lower ends of the upper charge air cooler portion being oriented inthe same direction as the upper and lower ends of the upper radiatorportion. One face of the upper radiator portion is disposed adjacent oneface of the upper charge air cooler portion, such that the ambientcooling air may flow in series through the upper radiator portion andthe upper charge air cooler portion. The lower charge air cooler portionis disposed in overlapping relationship and adjacent to the lowerradiator portion, with the upper and lower ends of the lower charge aircooler portion being oriented in the same direction as the upper andlower ends of the lower radiator portion. The other face of the lowerradiator portion is disposed adjacent one face of the lower charge aircooler portion, such that the ambient cooling air may flow in seriesthrough the lower charge air cooler portion and the lower radiatorportion.

The radiator portions are operatively connected such that the enginecoolant may flow between the lower manifold of the upper radiatorportion and the upper manifold of the lower radiator portion. The chargeair cooler portions are operatively connected such that the charge airmay flow between the lower manifold of the upper charge air coolerportion and the upper manifold of the lower charge air cooler portion.

In a further aspect, the present invention is directed to a heatexchanger apparatus comprising a first heat exchanger having twoportions for cooling a first fluid. Each first heat exchanger portionhas opposite front and rear faces through which ambient cooling airflows, a pair of manifolds, and fluid-carrying tubes extendingsubstantially directly therebetween. One of the first heat exchangerportions is disposed in a first plane, and the other of the first heatexchanger portions is disposed in a second plane, with the first andsecond planes being substantially parallel. The heat exchanger apparatusalso includes a second heat exchanger having two portions for cooling asecond fluid. Each second heat exchanger portion has opposite front andrear faces through which ambient cooling air flows, a pair of manifolds,and fluid-carrying tubes extending substantially directly therebetween.

One of the second heat exchanger portions is disposed in the secondplane in overlapping relationship and adjacent to the one of the firstheat exchanger portions, wherein one face of the one of the first heatexchanger portions is disposed adjacent one face of the one of thesecond heat exchanger portions. As a result, the ambient cooling air mayflow in series through the one of the first heat exchanger portions andthe one of the second heat exchanger portions. The other of the secondheat exchanger portions is disposed in the first plane in overlappingrelationship and adjacent to the other of the first heat exchangerportions, wherein the other face of the other of the first heatexchanger portions is disposed adjacent one face of the other of thesecond heat exchanger portions. As a result, the ambient cooling air mayflow in series through the other of the second heat exchanger portionsand the other of the first heat exchanger portions.

The first heat exchanger portions are operatively connected such thatthe first fluid may flow between a manifold of the one of the first heatexchanger portions and a manifold of the other of the first heatexchanger portions. The second heat exchanger portions are operativelyconnected such that the second fluid may flow between a manifold of theone of the second heat exchanger portions and a manifold of the other ofthe second heat exchanger portions.

The second heat exchanger portions may be operatively connected suchthat the second fluid may flow therebetween through a conduit extendingfrom and along the manifold of the one of the second heat exchangerportions to and along the manifold of the other of the second heatexchanger portions. The conduit may contain at least one stiffeningmember.

The first heat exchanger portions may be operatively connected such thatthe first fluid may flow between a manifold of the one of the first heatexchanger portions and a manifold of the other of the first heatexchanger portions adjacent at least one side of the first heatexchanger portions, or around at least one side of the second heatexchanger portions.

A further related aspect of the invention provides a method for coolingfluids used in an engine of a motor vehicle, comprising providing a heatexchanger assembly as described above, flowing the first fluidsequentially or in parallel through the one and the other of the firstheat exchanger portions, and flowing the second fluid sequentiallythrough the one and the other of the second heat exchanger portions. Themethod also includes flowing cooling air through the heat exchangerassembly such that ambient cooling air flows in series through the oneof the first heat exchanger portions and the one of the second heatexchanger portions, and ambient cooling air flows in series through theother of the second heat exchanger portions and the other of the firstheat exchanger portions.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention believed to be novel and the elementscharacteristic of the invention are set forth with particularity in theappended claims. The figures are for illustration purposes only and arenot drawn to scale. The invention itself, however, both as toorganization and method of operation, may best be understood byreference to the detailed description which follows taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a perspective view of a prior art radiator/charge air coolerheat exchanger package.

FIG. 2 is a side elevational view of one embodiment of theradiator/charge air cooler heat exchanger package of the presentinvention.

FIG. 3 is a top plan view of the radiator of the radiator/charge aircooler package of FIG. 2.

FIG. 4 is a front elevational view of the split charge air coolerportions of the heat exchanger package of FIG. 2, without the radiatorportions, and showing cooling fins over only a portion of the tubes ofthe core.

FIG. 5 is a front elevational view of the split radiator portions of theheat exchanger package of FIG. 2, without the charge air coolerportions, and showing cooling fins over only a portion of the tubes ofthe core.

FIG. 6 is a perspective view of the radiator/charge air cooler packageof FIG. 2.

FIG. 7 is a perspective view of an alternate heat exchanger package.

FIG. 8 is a plan or side elevational view of the radiator/charge aircooler heat exchanger package of the present invention in relation to acooling fan.

FIG. 9 is a side cross-sectional view of a portion of the heat exchangerpackage of the present invention showing one embodiment of theconnecting manifold between the two charge air cooler units.

FIG. 10 depicts a cross-section of a perspective view of anotherembodiment of the connecting manifold between the two charge air coolerunits, which is cast in a single unit.

FIG. 11 depicts a cross-section of a perspective view of the sameconnecting manifold as shown in FIG. 11, except that it is welded ofseveral sections.

FIG. 12 is perspective view of a portion of the heat exchanger packageof the present invention showing one embodiment of a connection betweenthe two radiator units, with the charge air cooler (CAC) units removed.

FIG. 13 is a perspective view of fluid connections between the radiatorunits and CAC units, with the CAC units removed, wherein the connectionsare contained within the overall width of the radiator and CAC units inthe heat exchanger package.

FIG. 14 is a perspective view of an alternate embodiment of thetwo-core-deep heat exchanger package of the present invention, in whichboth the radiator and CAC units are up- or downflow units, arrangedside-by-side.

FIG. 15 is a top plan view of the alternate heat exchanger package ofFIG. 14, showing the crossover manifold configuration of the charge aircooler units.

FIG. 16 is a elevational view of the back side of the alternate heatexchanger package of FIG. 14.

FIG. 17 is a rear perspective view of a preferred embodiment of the CACportion of the radiator/charge air cooler heat exchanger package of thepresent invention, to be used in conjunction with the radiator units ofFIG. 18, in which both the CAC units are downflow units.

FIG. 18 is a rear perspective view of a preferred embodiment of theradiator portion of the radiator/charge air cooler heat exchangerpackage of the present invention, to be used in conjunction with the CACunits of FIG. 17, in which both the radiator units are cross flow units,connected in parallel.

FIG. 19 is a side elevational view of the combined radiator/charge aircooler heat exchanger package employing the CAC units of FIG. 17 and theradiator units of FIG. 18.

FIG. 20 is a rear perspective view of a first alternate embodiment ofthe radiator units of FIG. 18, connected in series.

FIG. 21 is a rear perspective view of a second alternate embodiment ofthe radiator units of FIG. 18, connected in series.

FIG. 22 is a side elevational view, partially cut away, showing thecombined radiator/charge air cooler heat exchanger combination of thepresent invention mounted under the hood of a highway truck.

FIG. 23 shows alternate locations of the combination radiator/charge aircooler heat exchanger package of the present invention mounted in therear of a highway bus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In describing the preferred embodiment of the present invention,reference will be made herein to FIGS. 2-23 of the drawings in whichlike numerals refer to like features of the invention.

The preferred embodiment of the present invention is a cooling packageutilizing a radiator in two portions and a charge air cooler (CAC) intwo portions. The charge air cooler is arranged so that the entering hotcharge air is directed into the first portion of the charge air cooler,which is located downstream in the direction of cooling air flow fromthe first portion of the radiator. The partially cooled charge airexiting the first portion of the charge air cooler is then directed intothe second portion of the charge air cooler, which is located upstreamin the direction of cooling air flow from the second portion of theradiator. In this way, the exiting charge air is cooled by the coolestcooling air. To minimize charge air pressure drop through the charge aircooler portions, the charge air cooler portions are designed in adownflow configuration such that they have the greatest number of shorttubes, as opposed to being in a crossflow configuration with a smallernumber of longer tubes. The radiator portions in the invention coolingpackage are connected so that the engine coolant flows through the twoportions in parallel, thereby providing low coolant pressure drop andimproving the filling and de-aeration characteristics of the radiator.By making both the radiator and the charge air cooler in two portions,the preferred cooling package becomes only two units deep, as opposed tohaving the radiator in one piece and the charge air cooler in twoportions, placing one charge air cooler portion in back of the upperpart of the radiator and the other in front of the lower part of theradiator. Further, since the charge air which becomes partially cooledin the first portion of the charge air cooler has reduced volume, thesecond portion of the charge air cooler can be made with a thinner core.This reduction in core depth provides room for an air conditioningcondenser to be added to the cooling package.

In conventional cooling packages, the heat transfer performance isnormally a tradeoff between the radiator and the charge air cooler. Whenthe performance of one is improved, the performance of the othertypically suffers. In the preferred cooling package of the presentinvention, the hot charge air is partially cooled in the rear firstportion of the charge air cooler and is only directed into the frontsecond portion of the charge air cooler when it has cooled sufficientlyso that it will not deteriorate the performance of the radiator portionbehind it. This essentially decouples the performance of the charge aircooler from that of the radiator, allowing both to be optimized, withthe front radiator portion seeing an optimum approach differential(difference between the temperature of the entering coolant and theambient air).

A first embodiment of the heat exchanger package of the presentinvention is depicted in FIGS. 2-6. A combined, integrated heatexchanger package 20 preferably comprises a first heat exchanger havingat least two vertically split and separated units or portions 21, 22 forcooling a first fluid, preferably a radiator for use in cooling liquidengine coolant from an engine of a motor vehicle or other internalcombustion engine, and another heat exchanger having at least two splitunits or portions 30, 32 for cooling a second fluid, preferably chargeair coolers for cooling compressed charge air from a turbo orsupercharger of an internal combustion engine. Although engine coolantwill be used to exemplify the first fluid, and compressed charge airwill be used to exemplify the second fluid, any other fluids may besubstituted. Both heat exchangers are normally in an upstanding,essentially vertical position, and are preferably rectangular in shape,and the width and length of the combined heat exchanger package isconsistent with the requirements of the truck or bus enginecompartments. Radiator units 21, 22 of the present invention may be downflow type radiators, wherein engine coolant 40 enters the first radiatorunit 21 through an upper manifold or tank 24 a extending substantiallythe entire width of the radiator. The coolant is then distributed frommanifold 24 a into attached core 26 a having an otherwise conventionalconstruction, which generally comprises downwardly extending tubes 23connected by cooling fins 29 (FIG. 5), so that ambient cooling air 46may flow from the front face 28 a of the core through and out of therear face 28 b. After being cooled by the ambient air, the coolant thencollects in attached lower manifold or tank 24 b also extending acrossthe width of the radiator. From manifold 24 b, the coolant is thentransferred to separate radiator unit 22 (which is constructed in thesame manner as unit 21) into upper manifold 24 c, through core 26 b,into lower manifold 24 d and out through the coolant outlet for return48 to the engine. As will be explained below, ambient cooling air firstpasses through one of the charge air cooler units before flowing throughradiator unit 22 front face 28 c, radiator core 26 b, and rear face 28d.

The charge air cooler (CAC) of the present invention preferablycomprises a pair of vertically split and separated units or portions 30,32 (FIGS. 2 and 4). Upper CAC unit 30 is disposed in an overlappingfashion with radiator upper unit 21, so that the upper edge 39 a andsides 33 a, 33 b of CAC unit 30 are essentially coincident with andbehind the upper edge 25 a and sides 27 a, 27 b of radiator unit 21,with respect to the direction of cooling air 46. Front face 35 a of CACunit 30 is abutted to or slightly spaced from rear face 28 b of radiatorunit 21. CAC unit 30 contains an upper tank or manifold 34 a and a lowertank or manifold 34 b and a core 37 a attached therebetween, eachextending substantially the full width of the charge air cooler unit.Lower CAC unit 32 is positioned in front of radiator lower unit 22, withrespect to air flow direction 46, and the lower end 39 d and sides 33 a,33 b of unit 32 are essentially coincident with the lower end 25 d andlower sides 27 a, 27 b of radiator unit 22. Rear face 35 d of CAC unit32 is abutted to or slightly spaced from front face 28 c of radiatorunit 22. CAC unit 32 contains an upper tank or manifold 34 c and a lowertank or manifold 34 d and a core 37 b attached therebetween, eachextending substantially the full width of the charge air cooler unit.Both CAC cores 37 a, 37 b are conventional tube and fin construction.Lower manifold 34 b of CAC unit 30 is operatively connected to uppermanifold 34 c of CAC unit 32, so that charge air may flow therebetween.

The charge air cooler units of FIGS. 2-6 are preferably either up ordown flow units, and not cross flow units. Thus, as shown in FIG. 6, theentering heated compressed charge air 50 flows through manifold 34 a anddownward 52 to be cooled in core 37 a, made up of otherwise conventionalcharge air cooler tubes and cooling fins, and collected into a lowermanifold 34 b. This compressed charge air 54 is then transferred to theupper manifold 34 c of lower CAC unit 32, where the now partially cooledcharge air 56 then flows downward through core 37 b, into lower manifold34 d, and out as cooled compressed air 58 to be routed to the engine airintake manifold.

As shown in more detail in FIG. 4, each of the cores 37 a, 37 b for theCAC units 30, 32 comprise spaced, vertically extending tubes 36, betweenwhich are disposed serpentine cooling fins 38, oriented to permitcooling air flow through the unit. Such fins should extend between allof the tubes in the core. These tubes may be two (2) rows deep, as shownin FIG. 2, or any other configuration. Preferably, both charge aircooler units 30 and 32 have a horizontal width, measured in thedirection of the manifolds, which is greater than the vertical height ofeach of the units, measured between the manifolds. Improved heatexchanger package performance, and in particular, improved performanceof the charge air cooler units as a result of reduced charge airpressure drop, has been obtained by utilizing tubes 36 which are asshort as possible and as numerous as possible, given the configurationof the charge air cooler unit. As shown in this embodiment, charge aircooler units 30 and 32 employ tubes 36 which are oriented with theshorter vertical height of each of the units so that there are a largernumber of shorter tubes, as contrasted to the smaller number of longertubes as used in the cross flow CAC unit of FIG. 1.

Cores 26 a, 26 b for radiator units 21, 22 are shown in FIG. 5 as downflow units having cooling fins 29 extending between spaced, verticallyextending tubes 33 to permit cooling air flow through the unit. Suchfins should extend between all of the tubes in the core. These tubes 23may be two (2) rows deep, as shown in FIG. 2, or any otherconfiguration. Like the CAC units, the radiator units 21, 22 aredepicted in FIG. 5 as down flow units, with the tubes extending in thedirection of the shorter dimension of the unit, the height, so that alarge number of tubes are employed. Alternatively, when the pressuredrop of the coolant in the radiator is not critical, the radiator unitscan be cross-flow units, where the tubes extend in the direction of thelength of the longer, width dimension of the unit, with a fewer numberof tubes being employed.

Heat exchanger cores 26 a, 26 b, 37 a, 37 b can be constructed oftypical materials, for example aluminum, brass or copper tubes and fins.Manifolds 24 a, 24 b, 24 c, 24 d, 34 a, 34 b, 34 c, 34 d may be anyconventional materials such as plastic, aluminum, brass or copper.

FIG. 7 depicts another embodiment 20′ of the present invention which isstructurally identical to the previous embodiment, with the differencebeing that the radiator and charge air cooling units are rotated 90°, sothat the radiator and CAC units are horizontally separated. As before,manifolds 24 a, 24 b, 24 c, 24 d of radiator units 21 and 22 may beoriented in the same direction as manifolds 34 a, 34 b, 34 c, 34 d ofGAG units 30 and 32. In this embodiment, all of the manifolds of theradiator and charge air cooler units are vertically oriented andhorizontally spaced and, consequently, the fluid flow through the nowhorizontal tubes within the cores of the respective radiator and chargeair cooler units is now horizontal. However, the performance of the heatexchanger package in the embodiment of FIG. 7 is substantially the sameas that in the embodiment of FIGS. 2-6 since the charge air cooler tubesare as short and as numerous as possible given that the horizontal widthof each charge air cooler unit is less than its vertical height.

FIG. 8 depicts the heat exchanger package 20, 20′ of the previousembodiments in relation to a cooling suction fan having fan blades 62powered by a fan motor 60. The heat exchanger package 20, 20′ is in linewith the area swept by the fan blades to move the outside ambientcooling air 46 through each of the CAC units 30, 32 and radiator units21, 22. Radiator manifolds 24 b, 24 c and CAC manifolds 34 b, 34 c maybe positioned in line with the center of the fan blades 62 and fan motor60, where airflow is low or nearly zero. A fan shroud (not shown) may bepositioned circumferentially around the fan blades and the heatexchanger package top and side edges to contain and direct the airflow.The heat exchanger package is configured so that one radiator unit, 21,is aligned with one CAC unit, 32, in the same plane normal to thedirection of cooling air flow 46, so that the cooling air flows inparallel through these radiator and CAC units. The other radiator unit,22, is aligned with the other CAC unit, 30, also in the same planenormal to the direction of cooling air flow 46, so that the cooling airflows in parallel through these radiator and CAC units. Radiator/CACunits 22, 32 are in an abutted or closely spaced relationship with andconnected in series to the radiator/CAC units 21, 30 and are aligned sothat ambient cooling air 46 passes through both radiator and CAC units21 and 30, and radiator and CAC units 32 and 22, in a serial orsequential manner. The front and back faces of radiator/CAC units 21 and32 and the front and back faces of radiator/CAC units 22 and 30 are alsopreferably in the same respective planes, as shown in FIG. 8.

In operation, ambient cooling air 46 presented to approximately half ofthe heat exchanger package 20 or 20′ flows sequentially and in seriesthrough the free front face 28 a of radiator unit 21, through core 26 a,out through the rear face 28 b and, now having been heated to aboveambient temperature, then immediately flows through adjacent front face35 a of CAC unit 30. After passing through CAC core 37 a, the coolingair passes out through free rear face 35 b. In the other approximatelyhalf of heat exchanger package 20 or 20′, parallel ambient air 46 flowssequentially and in series through free front face 35 c of core 37 b ofCAC unit 32, and out of CAC rear face 35 d and, now having been heatedto above ambient temperature, then immediately through adjacent face 28c of radiator unit 22. After passing through the radiator core 26 b, theambient cooling air then exits through free rear face 28 d of radiatorunit 22. Notwithstanding the fact that it is heated as it passes throughthe fins of the radiator and CAC units, unless otherwise specified, theterm ambient air includes all of the cooling air as it passes throughthe heat exchanger package.

As shown in FIG. 6, the operational flow of fluid to be cooled is suchthat the initially hot engine coolant 40 is received in manifold 24 a ofradiator unit 21 and cooled as it passes 42 through radiator core 26 a,given that ambient air 46 is at a lower temperature than the incomingengine coolant 40. The partially cooled engine coolant is thentransferred 44 from manifold 24 b to manifold 24 c of radiator unit 22,where it passes 45 through radiator core 26 b and manifold 24 d, and out48 to return to the engine at a cooler temperature. Incoming compressedcharge air 50 is normally at a higher temperature than the incomingengine coolant, and is initially passed through upper charge air coolerunit 30. This heated charge air flows through core 37 a and is thencooled by air 46, after that air passes through and is heated byradiator upper core 26 a of radiator unit 21. The partially cooledcompressed charge air 54 then passes from lower manifold 34 b to uppermanifold 34 c of lower CAC unit 32. CAC unit 32 is in front of radiatorlower unit 22 with respect to the cooling air flow, and as the chargeair 56 passes downward through core 37 b, it is cooled by the freshambient air before it passes out through manifold 34 d of CAC unit 32 ascooled compressed air 58, which is then routed to the air intakemanifold of the engine.

The flow of ambient cooling air may be reversed for the embodimentsdescribed herein, so that it flows in direction 46′ (FIGS. 6 and 7). Toaccomplish this, a blower fan may be used in place of the suction fan toblow air first through the fan and then through the heat exchangerpackage. Additionally, the flow of fluids to be cooled may be reversedfrom that described above. The cooling performance of the heat exchangerpackage, including the CAC units, will be the same when reversing theflow of the ambient cooling air, so that it flows in direction 46′, andreversing the flow of the charge air, so that the charge air entersthrough manifold 34 d and exits through manifold 34 a.

The sides and upper and lower ends of the CAC and radiator units arepreferably aligned, so that there are no non-overlapping regions betweenthe top, bottom or sides of the radiator and the corresponding top,bottom and sides of the CAC units. However, in alternate embodiments,the heat exchanger package of the present invention may include suchnon-overlapping regions. For example, as shown in FIG. 8, radiator ends25 a′ or 25 d′ adjacent manifolds 24 a, 24 d, respectively, may extendabove and below the corresponding charge air cooler unit ends 39 a, 39d, adjacent manifolds 34 a, 34 d, respectively. Alternatively, ends 39a′, 39 d′ of the charge air cooler units may extend above and below theupper and lower ends 25 a, 25 d of the radiator units. As shown in FIG.3, it is also possible for there to be non-overlapping regions along thesides of the heat exchanger package. One or both of sides 27 a′, 27 b′of the radiator units may extend beyond the sides of the heat exchangerunits 33 a, 33 b. Alternatively, any of the charge air cooler sides 33a′, 33 b′ may extend beyond the sides 27 a, 27 b of the radiator units.In such cases, the radiator and CAC units may have different widths. Ifany such non-overlapping regions are used, the portions of either of thecharge air cooler units or radiator extending beyond and behind theother will then receive fresh ambient air. Additional heat exchangerstypically employed in motor vehicles may be used in the heat exchangerpackage of the present invention, such as engine oil and transmissionoil coolers, and air conditioning condenser units may also be used,either in front of or behind upper or lower portions of the package.

One embodiment of the manifold connection between the charge air coolerunits is depicted in FIG. 9. Core 37 a of CAC unit 30 has on it a lowerend manifold 34 b, and CAC unit 32 has on its upper end manifold 34 c,both contained within transition conduit 64. As depicted, an airpassageway or conduit 66 formed by duct walls 68 a, 68 b extends betweenmanifolds 34 b and 34 c, along substantially their full lengths, anddirectly and operatively connects the CAC units 30, 32 substantiallyalong their full widths and in their different planes to permit airflowtherebetween. Other preferred embodiments of the connecting manifoldsare depicted in cross-section in FIGS. 10 and 11, wherein the transitionconduit 64 a is as-cast as a single, integral unit 64 a (FIG. 10) or isa welded unit 64 b made up of four formed sections joined by welds 110(FIG. 11). In both embodiments, tube openings 102 a, 102 b receive CACtubes in polymeric grommets from cores 37 a, 37 b, respectively, tocreate the tube-to-header joints. (As shown, these CAC tubes areone-deep through the thickness of the core, as opposed to the two deeptube arrangement of FIG. 2, for example.) A central, vertical stiffeningrib 106 extends from top to bottom within the manifold conduit, alongsubstantially the full width of the CACs, to resist bursting as a resultof the internal charge air pressure (generally about 50-55 psig), andcontains multiple openings 104 for charge air passage therethrough.Multiple stiffening ribs, with spaces or openings between for charge airflow, may also be used across the width of the CAC manifolds.Alternatively, there may be employed one or more internal transversestiffening ribs at right angles to the longer dimension of themanifolds.

In FIG. 12 there is shown an embodiment of the operative coolantconnection between radiator units 21, 22, with the CAC units removed.Manifolds 24 b, 24 c each have extensions 124 b, 124 c, respectively,that extend outward from a side of the radiator units, and utilizeclamps 114 and/or hose 112 to provide for coolant flow between the two.Preferably, a similar extension and connection is provided around theopposite side of the radiator units. This radiator unit coolantconnection may then be used in conjunction with the CAC unit charge airconnection of FIGS. 9, 10 and 11, which connect along the center of theCAC units.

FIG. 13 shows another embodiment of a coolant connection betweenradiator units 21, 22, in conjunction with CAC manifold transitionconduit 64, both mounted to frame 140. Pairs of coolant inlets/outlets131 and 132, on radiator manifolds 24 b, 24 c, respectively, connect onopposite ends to transition coolant connectors 134, to transfer coolantbetween the radiator units. In this embodiment, the coolant connectionis disposed adjacent a side, but within the width, of radiator units 21,22, so as not to widen the overall width of the heat exchanger package,and the width of conduit 64 between the CAC manifolds is shortenedaccordingly. In this case, the width of the CAC units would beapproximately the same as that of conduit 64, so that the CAC unitswould have a width less than the radiator units.

Another embodiment of the present invention is shown in FIGS. 14, 15 and16. This heat exchanger package 220 also has the two-core-deepconfiguration of the split radiator and CAC units as shown in theprevious embodiments. As before, radiator unit 221 and CAC unit 232 aredisposed side-by-side in one plane, and CAC unit 230 and radiator unit222 are side-by-side in another plane. As depicted, a portion of thecooling ambient air flow 246 is first through fins 229 of core 226 a inradiator unit 221 and fins 238 of core 237 b in CAC unit 232, and then,in parallel with this, a second portion of the cooling ambient air flow246 flows sequentially through the respective fins and cores of CAC unit230 and radiator unit 222. (As before, the cooling ambient air flow maybe reversed, as shown by direction 246′.) Like the previous embodiments,this embodiment utilizes up- or downflow cores, wherein the CAC tubes236 and radiator tubes 233 extending between their respective manifoldsare shorter than the width dimension of the manifolds. Where charge airpressure drop may not be of great a concern, the CAC and radiator tubesmay be made longer than the width dimension of the manifolds. As withthe previous embodiments, heat exchange package 220 may be rotated 90°so that the CAC and radiator unit cores are side-flow.

This embodiment of FIGS. 14-16 also provides a compact heat exchangerpackage. Charge air flow is initially into inlet 250, through manifold234 a, tubes 236, manifold 234 b, manifold 234 c, tubes 236, manifold234 d, and out of outlet 258. Engine coolant flow is initially intoinlet 240, through manifold 224 a, tubes 233, manifold 224 b, manifold224 c, tubes 233, manifold 224 d, and out of outlet 248. As shown inFIG. 15, a crossover section 280, passing over CAC unit manifolds 234 a,234 d, connects radiator manifolds 224 b, 224 c, to permit coolant flowtherebetween. A similar crossover section 290 at the lower end of theheat exchanger package connects CAC manifolds 234 b, 234 c to permitcharge air flow therebetween.

FIGS. 17-19 depict a preferred embodiment of the heat exchanger packageof the present invention. The split radiator and CAC units of heatexchanger package 320 are arranged in the manner depicted in FIGS. 2-6,but have some significant differences. The identification of thecomponents are consistent with previous numbering, except that theybegin with the numeral 3 in some instances. CAC units 330 and 332 againare configured as downflow heat exchangers, with charge air 50 enteringupper rear CAC unit 330 through inlet 350, being distributed throughhorizontal inlet manifold 334 a and passing 52 through core 337 a andtransition manifold 364 (extending substantially across the widths ofthe CAC units 330 and 332), where it enters lower front CAC unit 332 andpasses 56 through core 337 b, horizontal outlet manifold 334 d, and out58 through outlet 358. While the charge air passing through both CACunits is again cooled by cooling air 46, thickness t₂ of lower CAC unitcore 337 b is less than thickness t₁ of upper CAC unit core 337 a, sincethe charge air volume passing through the lower unit has been reduced asa result of being partially cooled by passage through the upper CACunit. As a result, there is additional space for the thickness of an airconditioning condenser 90 (FIG. 19) in front of lower CAC unit 332,relative to the cooling air flow. Alternately, the CAC units may beupflow units, with the sizes reversed from that shown (as would be seenif the heat exchanger package were rotated 180° in FIG. 19).

The radiator units of FIG. 18 are similar to those shown in the previousfigures, except that they are cross flow units having the manifoldsalong each of the sides, extending vertically along the height of theunits, with the tubes in cores 326 a and 326 b extending horizontally tocarry the engine coolant. Instead of flowing in series, i.e.,sequentially between the upper an lower radiator units, the coolantflows in parallel through both of the units. Coolant enters 40 intoupper radiator unit 321 through radiator inlet 340 and the flow is splitso that a first portion flows through vertical manifold 324 a, passes 42through core 326 a, through vertical manifold 324 b, and out 48 athrough radiator outlet 348 a. The second portion of the coolant passes44 into lower radiator unit 322 through hose 334 or other connectionbetween the radiator units, is distributed through vertical manifold 324c, passes 45 through core 326 b, through vertical manifold 324 d, andthen out 48 b through radiator outlet 348 b. Alternatively, the incominghot coolant 40 may be split before it enters inlet 340, and the secondportion flowed directly into manifold 324 c, in which case connector 334is not necessary. The parallel connection between the radiator units321, 322 results in a lower pressure drop.

Other coolant flow arrangements for the radiator units 321, 322 to beemployed in heat exchanger package 320 are shown in FIGS. 20 and 21,where the flow is in series through the units, rather than in parallelas in FIG. 18. In FIG. 20, coolant flow enters 40 through inlet 340 ofupper radiator unit 321, is distributed by vertical manifold 324 b sothat it passes 42 through core 326 a and through vertical manifold 324a, where it passes 44 downward through connector 334. In lower radiatorunit 322, the partially-cooled coolant then is distributed by verticalmanifold 324 c so that it passes 45 through core 326 b and throughvertical manifold 324 d, where it exits 48 through radiator outlet 348.The flow is reversed in FIG. 21, where coolant flow enters 40 throughinlet 340 of lower radiator unit 322, is distributed by verticalmanifold 324 d so that it passes 42 through core 326 b and throughvertical manifold 324 c, where it passes 44 upward through connector334. In upper radiator unit 322, the partially-cooled coolant then isdistributed by vertical manifold 324 a so that it passes 45 through core326 a and through vertical manifold 324 b, where it exits 48 throughradiator outlet 348. Since all of the coolant flows through bothradiator units in FIGS. 20 and 21, coolant flow is faster, which bringsthe possibility of better heat transfer, although there is a largerpressure drop.

The heights of the CAC and radiator units are shown in FIGS. 17-21 to beapproximately the same; however, the height of the units may vary,depending on the application, and may even all be different. It has beenfound useful to construct the upper CAC and radiator units with an equalheight hi greater that the equal height h₂ lower CAC and radiator units,respectively (FIG. 19). Likewise, the widths of the CAC and radiatorunits as shown in FIGS. 17-21 may be the same, or they may be different,as discusser earlier in connection with FIGS. 3 and 13. To complete thepackage, fairings and a fan shroud 90 may be employed to ensure thatcooling air 46 does not flow around the split CAC and radiator units.

Referring to FIG. 22, a heavy duty highway truck 70 is shown includingengine 72 located in engine compartment 76 at the front portion of thetruck. The vehicle includes a lower frame 74 having the combinedradiator/CAC heat exchanger package 20, 20′, 220, 320 mounted verticallyat the front end of engine compartment 76. The fan is mounted within fanshroud 78 positioned behind the heat exchanger package. The radiatorunits are operatively connected to the cooling system of engine 72 byinlet hose 71 a and outlet hose 71 b which provide for flow of theengine coolant from and to the engine. The charge air cooler units areoperatively connected between the engine turbo or supercharger and theengine air intake manifold by inlet hose 73 a and outlet hose 73 b. FIG.23 depicts the heat exchanger package of the invention 20, 20′, 220, 320mounted at the rear of a bus behind grill 82, or at the side near therear (in phantom lines).

The cooling package depicted in the embodiment of FIGS. 17-19 wasinstalled in a highway truck with a prototype 550 horsepower enginedesigned to meet 2007 emissions requirements and dynamometer testedagainst the existing conventional cooling package of radiator withcharge air cooler mounted in front, and the test parameters and resultsare shown in Table 1 below.

TABLE I Top Tank Top Tank Test Package Test Engine Ram Air Amb Temp TempCAT TTTD TTTDc IMTD Number Type type Speed (mph) (F.) (F.) Corrected(F.) (F.) (F.) Spec Production C 1800 30 77 220 43 Spec Production R1800 35 110 220 43 Spec Production PT 1300 35 100 220 43 1a Production C1800 29 77.3 200.9 — 123.6 — 48.7 1b Split Series C 1800 30 77.3 168.1 —90.8 — 36.5 2a Production R 1800 35 84.6 203.3 203.2 123.7 116.6 49.1 2bSplit Series R 1800 35 85.0 181.6 172.4 96.6  87.4 38.6 Corrected FuelRate Corected Ambient Cap. CAT Ambient CAT Test Package CAC dP Fuel TempFuel Rate Correction Amb Cap. Cap. Correction Number Type (in. Hg) (F.)(lbs/hr) Factor (F.) (F.) (F.) Spec Production 4.5 199.1 Spec Production4.5 199.1 110 110   Spec Production 4.5 149.3 100 100   1a Production3.1 106.2 209.6 — 96.4 — — 1b Split Series 3.9 103.3 202.1 — 129.2 — —2a Production 3.0 107.0 207.7 0.0527 96.3 100.5 101.4 2b Split Series4.3 108.9 185.3 0.0748 123.4 114.8 132.6

The conventional cooling package is identified as Production and thecooling package of FIGS. 17-19 is identified as Split Series. Test typeC is performed under conditions designed to check charge air coolercapability and test type R is performed at rated power to check bothcharge air cooler and radiator capability. The engine manufacturer'sspecifications are given in the top three listed tests, labeled Spec. Ascan be seen in comparative test nos. 1 a and 1 b, for test type C, theconventional cooling package exceeded the specified maximum intakemanifold temperature differential (IMTD), or difference between intakemanifold temperature and ambient temperature, by 5.7° F. (3.2° C.) whilethe invention cooling package was 6.5° F. (3.6° C.) below the specifiedmaximum, a 12.2 (6.8° C.) improvement. At the same time, the inventioncooling package provided a 32.8° F. (18.2° C.) improvement (reduction)in the radiator top tank temperature (engine outlet coolant temperature)and a 32.8° F. (18.2° C.) improvement (increase) in ambient capability(the maximum operating ambient temperature at which the maximumallowable top tank temperature will not be exceeded) compared to theconventional cooling package.

As can be seen in comparative test nos. 2 a and 2 b, for test type R atrated power, the conventional cooling package exceeded the specifiedmaximum IMTD by 6.1° F. (3.4° C.) while the invention cooling packagewas 4.4° F. (2.4° C.) below the specified maximum, a 10.5° F. (5.8° C.)improvement. At the same time, the invention cooling package provided a26.7° F. (14.8° C.) improvement in the radiator top tank temperature anda 27.1° F. (15.1° C.) improvement in ambient capability. The improvedperformance of the invention cooling package was achieved while fittingin the same space as the conventional cooling package and while meetingthe engine manufacturer's requirements for charge air pressure drop.This performance is more than sufficient to meet the emissionrequirements of 2007 and to allow for higher engine horsepower. To date,it is believed that this performance is unmatched by prior art heatexchanger packages.

Thus, the heat exchanger package of the present inventions provides acombination radiator and charge air cooler which achieves high heattransfer performance with a minimal frontal area, while minimizingpressure loss to the fluids. It is particularly useful for coolingfluids such as engine coolant and charge air used in the engine of aheavy-duty truck, highway bus or other motor vehicle. In addition, thefact that both the radiator and charge air cooler are split into twosmaller units makes them lighter and easier to handle in manufacturingand in individual replacement.

While the present invention has been particularly described, inconjunction with a specific preferred embodiment, it is evident thatmany alternatives, modifications and variations will be apparent tothose skilled in the art in light of the foregoing description.Variations of the preferred embodiment may be required to suit certainapplications, based on available space and considerations involving therouting of hose connections to the heat exchangers. While thesevariations may not provide the ultimate in heat transfer performance andlow fluid pressure drop as does the preferred embodiment, neverthelessthey are believed to provide improved performance compared to the priorart. Some of the variations may include a change in orientation of theradiator and charge air cooler portions (from downflow to cross flow,and vice-versa) and/or a change in the operative connection of theradiator and charge air cooler portions, e.g., from series to parallelconnection. It is therefore contemplated that the appended claims willembrace any such alternatives, modifications and variations as fallingwithin the true scope and spirit of the present invention.

1. A heat exchanger apparatus comprising: a first heat exchanger havingtwo portions for cooling a first fluid, each first heat exchangerportion having opposite front and rear faces through which cooling airflows, opposite first and second ends adjacent the faces, sides adjacentthe faces between the first and second ends, and including tubes throughwhich the first fluid may flow while being cooled; a second heatexchanger having two portions for cooling a second fluid, each secondheat exchanger portion having opposite front and rear faces throughwhich cooling air flows, opposite first and second ends adjacent thefaces, and sides adjacent the faces between the first and second ends,and including tubes through which the second fluid may flow while beingcooled, one of the second heat exchanger portions being disposed inoverlapping relationship and adjacent to one of the first heat exchangerportions, wherein one face of the one of the first heat exchangerportions is disposed adjacent one face of the one of the second heatexchanger portions, such that the ambient cooling air may flow in seriesthrough the one of the first heat exchanger portions and the one of thesecond heat exchanger portions, the other of the second heat exchangerportions being disposed in overlapping relationship and adjacent to theother of the first heat exchanger portions, wherein the other face ofthe other of the first heat exchanger portions is disposed adjacent oneface of the other of the second heat exchanger portions, such that thecooling air may flow in series through the other of the second heatexchanger portions and the other of the first heat exchanger portions,the first heat exchanger portions being operatively connected such thatthe first fluid may flow either in series or in parallel through thefirst heat exchanger portions, and the second heat exchanger portionsbeing operatively connected such that the second fluid may flow inseries between the one and the other of the second heat exchangerportions.
 2. The heat exchanger apparatus of claim 1 wherein the firstheat exchanger portions are operatively connected such that the firstfluid may flow in parallel through the first heat exchanger portions,with one portion of the first fluid flowing through the one of the firstheat exchanger portions and another portion of the first fluid flowingthrough the other of the first heat exchanger portions.
 3. The heatexchanger apparatus of claim 1 wherein the first heat exchanger portionsare operatively connected such that the first fluid may flow in seriesthrough both of the first heat exchanger portions, with all of the firstfluid flowing through both first heat exchanger portions.
 4. The heatexchanger apparatus of claim 1 wherein the first heat exchanger portionsare cross flow units, including a manifold along each of the sides withthe first heat exchanger portion tubes connecting the manifolds.
 5. Theheat exchanger apparatus of claim 1 wherein the second heat exchangerportions are up- or down flow units, including a manifold between eachof the sides at upper and lower ends of each of the portions with thesecond heat exchanger portion tubes connecting the manifolds.
 6. Theheat exchanger apparatus of claim 5 wherein the second heat exchangerportions are down flow units and wherein the one of the second heatexchanger portions has greater thickness between faces than the other ofthe second heat exchanger portions.
 7. The heat exchanger apparatus ofclaim 5 wherein the second heat exchanger portions are upflow units andwherein the other of the second heat exchanger portions has greaterthickness between faces than the one of the second heat exchangerportions.
 8. The heat exchanger apparatus of claim 1 wherein the firstand second heat exchanger portions have heights between the first andsecond ends thereof, and wherein the heights of the ones of the firstand second heat exchanger portions are greater than the heights of theothers of the first and second heat exchanger portions.
 9. The heatexchanger apparatus of claim 1 wherein the first and second heatexchanger portions have heights between the first and second endsthereof, and wherein the heights of the ones of the first and secondheat exchanger portions are substantially the same as the heights of theothers of the first and second heat exchanger portions.
 10. The heatexchanger apparatus of claim 1 wherein the first and second heatexchanger portions have heights between the first and second endsthereof, and wherein the heights of the first and second heat exchangerportions are all different.
 11. The heat exchanger apparatus of claim 1wherein the first and second heat exchanger portions have widths betweenthe sides thereof, and wherein the widths of the first heat exchangerportion are substantially the same as the widths of the second heatexchanger portion.
 12. The heat exchanger apparatus of claim 1 whereinthe first and second heat exchanger portions have widths between thesides thereof, and wherein the widths of the first heat exchangerportion are greater than the widths of the second heat exchangerportion.
 13. The heat exchanger apparatus of claim 1 wherein the one ofthe first heat exchanger portions and the other of the second heatexchanger portions are disposed in a substantially same first plane, andwherein the other of the first heat exchanger portions and the one ofthe second heat exchanger portions are disposed in a substantially samesecond plane.
 14. The heat exchanger apparatus of claim 1 wherein thefirst heat exchanger portions are operatively connected such that thefirst fluid may flow between the one of the first heat exchangerportions and the other of the first heat exchanger portions adjacent atleast one side of the first heat exchanger portions.
 15. The heatexchanger apparatus of claim 1 wherein the first and second heatexchanger portions have widths between the sides thereof, and whereinthe second heat exchanger portions are operatively connected such thatthe second fluid may flow therebetween through a conduit extendingsubstantially across the widths of the second heat exchanger portions.16. The heat exchanger apparatus of claim 1, wherein the first heatexchanger is a radiator for cooling engine coolant and the second heatexchanger is a charge air cooler for cooling charge air, and wherein:the radiator has upper and lower portions, with each radiator portionhaving opposite upper and lower ends adjacent the faces of the radiatorportion; the charge air cooler has upper and lower portions, with eachcharge air cooler portion having opposite upper and lower ends adjacentthe faces of the charge air cooler portion, and upper and lowermanifolds extending across the upper and lower ends, respectively, ofeach charge air cooler portion, the upper charge air cooler portionbeing disposed in overlapping relationship and adjacent to the upperradiator portion with the upper and lower ends of the upper charge aircooler portion being oriented in the same direction as the upper andlower ends of the upper radiator portion, wherein the rear face of theupper radiator portion is disposed adjacent the front face of the uppercharge air cooler portion and the upper manifold of the upper charge aircooler portion is disposed adjacent the upper end of the upper radiatorportion, the lower charge air cooler portion being disposed inoverlapping relationship and adjacent to the lower radiator portion withthe upper and lower ends of the lower charge air cooler portion beingoriented in the same direction as the upper and lower ends of the lowerradiator portion, wherein the front face of the lower radiator portionis disposed adjacent the rear face of the lower charge air coolerportion and the lower manifold of the lower charge air cooler portion isdisposed adjacent the lower end of the lower radiator portion, the lowerend of the upper charge air cooler portion being substantially in linewith and opposite the upper end of the lower charge air cooler portion,the charge air cooler portions being operatively connected by a conduitextending from the lower manifold at the lower end of the upper chargeair cooler portion to the upper manifold at the upper end of the lowercharge air cooler portion such that the charge air may flow through theconduit between the upper charge air cooler portion and the lower chargeair cooler portion.
 17. The heat exchanger apparatus of claim 16,wherein the upper radiator portion and the lower charge air coolerportion are disposed substantially in a first plane, and wherein thelower radiator portion and the upper charge air cooler portion aredisposed substantially in a second plane, the first and second planesbeing substantially parallel.
 18. A combined radiator and charge aircooler package comprising: a radiator having upper and lower portionsfor cooling engine coolant, each radiator portion having opposite frontand rear faces through which ambient cooling air flows, opposite upperand lower ends adjacent the faces, and sides adjacent the faces betweenthe upper and lower ends, and including manifolds between the sides atupper and lower ends of each of the radiator portions and tubes throughwhich the engine coolant may flow connecting the radiator manifolds; acharge air cooler having upper and lower portions for cooling chargeair, each charge air cooler portion having opposite front and rear facesthrough which cooling air flows, opposite upper and lower ends adjacentthe faces, and sides adjacent the faces between the upper and lowerends, and including manifolds along the upper and lower ends and tubesthrough which the charge air may flow connecting the charge air coolermanifolds, the upper charge air cooler portion being disposed inoverlapping relationship and adjacent to the upper radiator portion,wherein one face of the upper radiator portion is disposed adjacent oneface of the upper charge air cooler portion, such that the ambientcooling air may flow in series through the upper radiator portion andthe upper charge air cooler portion, the lower charge air cooler portionbeing disposed in overlapping relationship and adjacent to the lowerradiator portion, wherein the other face of the lower radiator portionis disposed adjacent one face of the lower charge air cooler portion,such that the ambient cooling air may flow in series through the lowercharge air cooler portion and the lower radiator portion, the upperradiator portion and the lower charge air cooler portion beingsubstantially disposed in one plane, and the lower radiator portion andthe upper charge air cooler portion being substantially disposed inanother plane, the radiator portions being operatively connected suchthat the engine coolant may flow either in series or in parallel throughthe radiator portions, and the charge air cooler portions beingoperatively connected such that the charge air may flow in seriesbetween the upper charge air cooler portion and the lower charge aircooler portion.
 19. The combined radiator and charge air cooler packageof claim 18 wherein the radiator portions are operatively connected suchthat the engine coolant may flow in parallel through the radiatorportions, with one portion of the coolant flowing through the upperradiator portion and another portion of the coolant flowing through thelower radiator portion.
 20. The combined radiator and charge air coolerpackage of claim 18 wherein the radiator portions being operativelyconnected such that the engine coolant may flow in series through bothof the radiator portions, with all of the coolant flowing through bothradiator portions.
 21. The heat exchanger apparatus of claim 18 whereinthe upper charge air cooler portion has greater thickness between facesthan the lower charge air cooler portion.
 22. The heat exchangerapparatus of claim 18 wherein the lower charge air cooler portion hasgreater thickness between faces than the upper charge air coolerportion.
 23. A method for cooling fluids used in an internal combustionengine, comprising: providing a heat exchanger assembly comprising: afirst heat exchanger having two portions for cooling a first fluid, eachfirst heat exchanger portion having opposite front and rear facesthrough which cooling air flows, opposite first and second ends adjacentthe faces, sides adjacent the faces between the first and second ends,and including tubes through which the first fluid may flow while beingcooled; a second heat exchanger having two portions for cooling a secondfluid, each second heat exchanger portion having opposite front and rearfaces through which cooling air flows, opposite first and second endsadjacent the faces, and sides adjacent the faces between the first andsecond ends, and including tubes through which the second fluid may flowwhile being cooled, one of the second heat exchanger portions beingdisposed in overlapping relationship and adjacent to one of the firstheat exchanger portions, wherein one face of the one of the first heatexchanger portions is disposed adjacent one face of the one of thesecond heat exchanger portions, the other of the second heat exchangerportions being disposed in overlapping relationship and adjacent to theother of the first heat exchanger portions, wherein the other face ofthe other of the first heat exchanger portions is disposed adjacent oneface of the other of the second heat exchanger portions, flowing thefirst fluid in series or parallel through the first heat exchangerportions; flowing the second fluid in series between the one and theother of the second heat exchanger portions; and flowing ambient coolingair through the heat exchanger assembly such that ambient cooling airflows in series through the one of the first heat exchanger portions andthe one of the second heat exchanger portions, and ambient cooling airflows in series through the other of the second heat exchanger portionsand the other of the first heat exchanger portions, to cool the firstfluid in the first heat exchanger portions and the second fluid in thesecond heat exchanger portions.
 24. The method of claim 23 wherein thefirst fluid flows in parallel through the first heat exchanger portions,with one portion of the first fluid flowing through the one of the firstheat exchanger portions and another portion of the first fluid flowingthrough the other of the first heat exchanger portions.
 25. The methodof claim 23 wherein the first fluid flows in series through both of thefirst heat exchanger portions, with all of the first fluid flowingthrough both first heat exchanger portions.
 26. The method of claim 23wherein the first heat exchanger portions include a manifold along eachof the sides with the first heat exchanger portion tubes connecting themanifolds, and wherein the first fluid flows from one side of the firstheat exchanger portions to the other side of the first heat exchangerportions through the tubes.
 27. The method of claim 23 wherein thesecond heat exchanger portions include a manifold between each of thesides at upper and lower ends of each of the portions with the secondheat exchanger portion tubes connecting the manifolds, and wherein thesecond fluid flows between one end of the second heat exchanger portionsand the other end of the second heat exchanger portions through thetubes.
 28. The method of claim 23 wherein the second heat exchangerportions include a manifold between each of the sides at upper and lowerends of each of the portions with the second heat exchanger portiontubes connecting the manifolds, and wherein the second fluid flows fromthe lower manifold of the one of the second heat exchanger portions tothe upper manifold of the other of the second heat exchanger portions.29. The method of claim 23 wherein the second heat exchanger portionsinclude a manifold between each of the sides at upper and lower ends ofeach of the portions with the second heat exchanger portion tubesconnecting the manifolds, and wherein the second fluid flows from theupper manifold of the other of the second heat exchanger portions to thelower manifold of the one of the second heat exchanger portions.
 30. Themethod of claim 23 wherein the one of the first heat exchanger portionsand the other of the second heat exchanger portions are disposed in asubstantially same first plane, and wherein the other of the first heatexchanger portions and the one of the second heat exchanger portions aredisposed in a substantially same second plane, such that the ambientcooling air flows simultaneously through the one of the first heatexchanger portions and the other of the second heat exchanger portions,and simultaneously through the one of the second heat exchanger portionsand the other of the first heat exchanger portions.
 31. The method ofclaim 23 wherein the first fluid flows between the one of the first heatexchanger portions and the other of the first heat exchanger portionsadjacent at least one side of the first heat exchanger portions.
 32. Themethod of claim 23 wherein the first and second heat exchanger portionshave widths between the sides thereof, and wherein the second fluidflows between the second heat exchanger portions through a conduitextending substantially across the widths of the second heat exchangerportions.
 33. The method of claim 23 wherein the first heat exchanger isa radiator and the first fluid is engine coolant, and wherein the secondheat exchanger is a charge air cooler and the second fluid is chargeair, each of the radiator and the charge air cooler portions beingcooled by ambient air.
 34. The method of claim 23, wherein the firstheat exchanger is a radiator for cooling engine coolant and the secondheat exchanger is a charge air cooler for cooling charge air, andwherein: the radiator has upper and lower portions, with each radiatorportion having opposite upper and lower ends adjacent the faces of theradiator portion; the charge air cooler has upper and lower portions,with each charge air cooler portion having opposite upper and lower endsadjacent the faces of the charge air cooler portion, and upper and lowermanifolds extending across the upper and lower ends, respectively, ofeach charge air cooler portion, the upper charge air cooler portionbeing disposed in overlapping relationship and adjacent to the upperradiator portion with the upper and lower ends of the upper charge aircooler portion being oriented in the same direction as the upper andlower ends of the upper radiator portion, wherein the rear face of theupper radiator portion is disposed adjacent the front face of the uppercharge air cooler portion and the upper manifold of the upper charge aircooler portion is disposed adjacent the upper end of the upper radiatorportion, the lower charge air cooler portion being disposed inoverlapping relationship and adjacent to the lower radiator portion withthe upper and lower ends of the lower charge air cooler portion beingoriented in the same direction as the upper and lower ends of the lowerradiator portion, wherein the front face of the lower radiator portionis disposed adjacent the rear face of the lower charge air coolerportion and the lower manifold of the lower charge air cooler portion isdisposed adjacent the lower end of the lower radiator portion, the lowerend of the upper charge air cooler portion being substantially in linewith and opposite the upper end of the lower charge air cooler portion,the charge air cooler portions being operatively connected by a conduitextending from the lower manifold at the lower end of the upper chargeair cooler portion to the upper manifold at the upper end of the lowercharge air cooler portion; and including flowing coolant between theupper and lower radiator portions and flowing charge air through theconduit between the upper charge air cooler portion and the lower chargeair cooler portion.
 35. The method of claim 34, wherein the upperradiator portion and the lower charge air cooler portion are disposedsubstantially in a first plane, and wherein the lower radiator portionand the upper charge air cooler portion are disposed substantially in asecond plane, the first and second planes being substantially parallel,and including flowing cooling air through the heat exchanger assemblysuch that the cooling air flows sequentially between the upper radiatorportion and the upper charge air cooler portion, and the cooling airalso flows sequentially between the lower charge air cooler portion andthe lower radiator portion, to cool the engine coolant in the radiatorportions and the charge air in the charge air cooler portions.